Final answer:
In the term 'masthelcosis', 'helc' is the element that means 'ulcer'. This term refers to an ulceration in the breast.
Step-by-step explanation:
The element within the term masthelcosis that means 'ulcer' is helc, derived from 'helcos', which is a combining form signifying 'ulcer'. In medical terminology, prefixes, suffixes, and combining forms are used to describe conditions, procedures, or parts of the body. The term 'masthelcosis' refers to an ulceration (helcosis) in the breast (mast-). For example, a peptic ulcer is an ulcer in the lining of the stomach or duodenum often related to the bacterium Helicobacter pylori.